The advantages of liquid filling and packaging machines for filling plastic bags with a liquid product, such as milk or wine, has given rise to the need for a nozzle that is efficient in operation and that can be replaced for use with glands having varied diameters. Present day machines of this type each includes a nozzle that is structurally integrated with a filling head to solely fill a plastic bag with liquid product through a gland having a set diameter. When the machine is utilized for filling the bag through a gland having a different diameter, the entire filling head assembly must be removed and replaced to accommodate the same.